trade in

以旧换新, 买卖

例句与用法：

The jewellery firm is just a front for their illegal trade in diamonds.

该珠宝公司不过是进行非法的钻石交易的幌子。

The company was granted a charter trade in the occupied territory.

这家公司被授予特权，可以在被占领地区进行贸易活动。

The gas company is offering fifty pounds off a new cooker if you trade in your old one.

如果你用旧厨灶来折价的话，那家煤气公司愿以减价50英镑出售一套新厨灶。

The old trade in black ivory is on more.

昔日非洲黑奴的买卖已不复存。